JPS58202642A - Space diversity receiver - Google Patents

Abstract

PURPOSE:To enable the use even in a section inferior in propagation condition for a space diversity receiver which is provided to a master station in a time division multi-direction communication network, by monitoring the error factor of a demodulated signal independently in response to each slave station to perform the switch selection control. CONSTITUTION:A master station 100 contains conflict counting circuits 4 in numbers equal to slave sations A, B-H which require diversity. For instance, the burst receiving signal supplied from the sation A is received through a main antenna MA and a secondary antenna SA of the station 100 and demodulated by each receiver 2. The error pulses EP given from receivers 2 are counted by the circuit 4 for station A for the burst time during which the signals are received from the station A. The circuit 4 performs a control so that a signal switch 3 selects the receiving signal side having a better code error factor. When the burst time of the station A elapses, the circuit 4 holds its state and then restarts its function at the burst time of the station A after opening gates 5 and 6. The same operation is carried out also with other slave stations B-H.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates in particular to a space diversity system in a time division multidirectional communication network formed by a large number of scattered slave stations and a common master station.

The present invention relates to a space diversity receiving device provided in a master station.

Referring to FIG. 1, there is shown a time/minute opening direction communication system to which the present invention is applied. The master station 100 sends time-division multiplexed signals to a plurality of slave stations A.

B, . . . , H are transmitted all at once in continuous mode.

On the other hand, each slave station is synchronized with the master station's clock and transmits a signal in a stream to the master station during the time period assigned to it. Since the signals are arranged in an orderly manner on the time axis, they can be easily identified and reproduced using the master station's clock.

In such a time-division multidirectional communication network, when the propagation path between the master station and the slave stations is long distance or ocean propagation, it is necessary to apply space diversity to improve line quality.

On the other hand, as shown in Fig. 2, in the space diversity method of opposing lines for the purpose of communication between two points, the received signals from the main antenna MA and the sub antenna S'A are each demodulated and regenerated. There is a baseband switching method that switches and selects a demodulated signal with a lower bit error rate. In Fig. 2, 1 is a transmitter, and 2 is a transmitter that receives a signal from the main antenna MA or auxiliary antenna SA, outputs the entire demodulated signal, detects a code error in the demodulated signal, and generates an error pulse EPi.
3 is a signal switcher that switches the baseband signal demodulated by each receiver, and 4 is a signal switcher 3 that receives the error pulse EP from the two receivers 2, and switches the side with a lower error rate to the signal switcher 3. This is a competition counting circuit that generates a switching control signal CS that selects the demodulated signal.

However, if the baseband switching method shown in FIG. 2 is applied as is to the multidirectional communication system.

A master station receiving signals from a plurality of slave stations has the disadvantage that it cannot fully monitor and control the line status of each slave station independently, and a sufficient space diversity effect cannot be obtained.

An object of the present invention is to independently monitor the error rate of demodulated signals for each slave station and control switching selection in a space diversity receiving device provided in a master station in a time-division multidirectional communication network as shown in Fig. 1. Provides a space-diaperity receiving device.

The purpose is to eliminate the above drawbacks.

3- Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 3 is an embodiment of the space diversity method of the present invention. In FIG. 6, reference numeral 4 denotes a competition counting circuit, which is installed in the master station 100 in the number of slave stations A, B, . . . , H that require diversity.

5 is an error pulse EPi from the receiver 2 which is input to the contention counting circuit 4. The burst timing pulse BTP is used to count the error pulses EPi from the receiver 2 so as to count only the time periods when signals from each slave station are being received.
The first gate circuit 6 is used to output the control signal C8 of the contention counting circuit output that controls the signal switch 3, and the second gate circuit is also used to output the control signal C8 only during the time period when each slave station's signal is being received. be. In addition, burst timing nodes BTPA, corresponding to each of slave stations A, B, ..., H,
BTP, . . . BTPH are supplied from a timing generator circuit (not shown) in the signal processing circuit of the master station 100, which is a timing signal master.

With the above configuration, a node reception signal from station A, for example, is received by the main antenna MA and sub antenna SA of the master station 100, and demodulated by each receiver 2.On the other hand, each receiver 2 The error pulse EP from the station A is input to the contention counting circuit 4 for the A station and counted only during the burst time when the signal from the A station is being received. When the burst time of station A has passed, the contention counting circuit 4 maintains that state, and when the burst time of station A comes again, it gates its function. 5 and 6″f
f: Open and resume.

Similarly, for stations that require diversity, the B-station contention counting circuit is operated during the B-station burst time to switch the baseband signal for the B-station. Note that it is not necessary to provide a competition counting circuit for slave stations that do not require diversity, and the demodulated signal of one of the receivers is fixedly selected.

Figure 6 shows the transmission systems of the slave stations A-H and the diversity reception system of the master station 100, but since the reception systems of the slave stations receive in continuous mode, the reception systems of the slave stations and the diversity reception system of the master station are The conventional diversity method shown in FIG. 2 can be applied to the transmission system. In this way, a bidirectional diversity system can be constructed between the master station and the slave stations that require space diversity.

FIG. 4 shows gate circuits 5, 6. A specific example of the configuration of the competition counting circuit 4 is shown in FIG. 1, which is a 7flN bit counting circuit, and the value of N is determined to be an appropriate value in consideration of the detection time until switching. FIG. 5 shows a specific example of the configuration of the receiver 2.
Upon receiving the received signal R8, demodulated signal DATA of the burst signal is received.
'jz output demodulation circuit 8, a customary discriminator 9, a discriminator 10 whose error rate is artificially made worse, and a discriminator 9゜1
The comparator 11 compares the outputs of 0 and generates an error pulse EPi. When the error rate starts to deteriorate, the outputs of the discriminators 1 and 0 start to be erroneous, and an erroneous pulse occurs in the output of the comparator 11.

Can predict deterioration in line quality.

As explained above, according to the present invention, parsing can be realized,
This makes it possible to introduce a multi-directional communication system even in sections with poor propagation conditions, such as propagation by sea.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining a time-division multidirectional communication system to which the present invention is applied, FIG. 2 is a diagram showing a conventional space diversity system, and FIG. 3 is a diagram illustrating an embodiment of the present invention. ,
Figure 4 shows the competition counting circuit 4 and gate circuits 5 and 6 in Figure 3.
FIG. 5 is a circuit diagram showing a specific example of the configuration of the receiver 2 in FIG. 3. 100... Master station, A-H... Slave station, 1... Transmitter, 2... Receiver, MA... Main antenna, SA.
...Sub antenna 6...Signal switcher, 4...-Conflict counting circuit, 5...First gate circuit, 6...Second gate circuit, 7...Counting circuit, 8... - Demodulation circuit, 9 and 10... discriminator. 11...Comparator, EP...False 9 pulses, BTP
... Burst timing pulse, C8... Control signal. Preface 1

Claims (1)

[Claims] 1. A communication network is formed by a plurality of slave stations and one master station, and each slave station transmits data to the master station during the time slot assigned to it, and the master station In a space diversity receiving device provided in a master station in a time-division multidirectional communication system that receives burst signals from a slave station, the space diversity receiving device includes a first receiver having a main antenna, and a sub-antenna. a second receiver comprising a second receiver, and the first and second receivers each have a second receiver. demodulation means for demodulating the input signal from the antenna; and detection means for detecting a code error in a demodulated signal and generating an error pulse, and the space diversity receiving device was further provided for each slave station requiring space diversity. A competition counting means for competitively counting error pulses from the two receivers, and an input side and an output side of the competition counting means were provided. first and second gate means that open and close according to the burst timing signal of each slave station; A space diversity receiving device characterized in that a signal switch is controlled so that one of the signals having a lower error rate is selected.